If the insinuation is that people would rather watch the Mavericks than the Spurs, I don't buy that. I don't see the Mavericks playing a style that is appreciably more watchable than the style the Spurs now play. It's not like this is the 2003 up-and-down and in the high 100's Mavericks; FWIW, during the regular season, the Mavericks played at a slower offensive pace each night than the Spurs did.
I don't see the Mavericks having any real ratings-getter on the roster -- no Kobe, Shaq, Lebron, Wade. And I'm not sure that the average sports viewer who doesn't pay much attention to regular season NBA will hear "Dirk Nowitzki" and think "superstar;" they should, but I'm not sure he carries that clout yet. And I don't see the Mavericks having tremendous international appeal (outside of perhaps Germany).
If the Mavs reach the Finals and play Miami, the increase in ratings will have everything to do with bringing back the bedwetters who can't watch the NBA unless Shaq is involved. That, or the DWade crew. If the Mavs reach the Finals and play Detroit, I'm not sure viewership will increase appreciably, other than the influx of homes in Dallas that suddenly tune in.